1. Field of the Invention
The present invention relates to a resin molding type of semiconductor laser device, and to a method for manufacturing the same.
2. Description of the Related Art
Semiconductor laser devices have been utilized in the past for optical disk players, laser printers, and other such optical response devices. Semiconductor laser devices come in can types and resin molding types, for example, with a laser chip mounted to a frame.
As shown in FIG. 13, a can type of semiconductor laser device 1 comprises a laser chip 2 that emits laser light, and this laser chip 2 is mounted on the side of a rectangular heat-radiating body 3 that is parallel to the optical axis. This heat-radiating body 3 is erected on the top of a disk-shaped stem 4, and a cylindrical cap 5 is mounted around its periphery. A glass window is provided to the top of the cap 5, and the laser chip 2 faces the glass window 6 from the inside of the cap 5. Because the outside diameter of the stem 4 is larger than that of the cap 5, the outer periphery of the stem 4 that sticks out further than this cap 5 becomes a flange 7.
With the can type of semiconductor laser device 1 described above, when the laser chip 2 inside the cap 5 emits laser light, this laser light is emitted through the glass window 6. The laser chip 2 generates heat at this time, but because the inside of the cap 5 is hollow, this heat is radiated by the stem 4, which acts as a heat-radiating fin.
With the can type of semiconductor laser device 1 described above, since in structural terms the laser chip 2 is fixed with good precision to the stem 4, as shown in FIG. 14, laser light can generally be emitted accurately with respect to a device housing 8 if the shape of the flange 7 is utilized for mounting in a stepped hole 9 of the device housing 8.
However, the can type of semiconductor laser device 1 comprises numerous parts and has a complicated construction. In view of this, a semiconductor laser device in which the laser chip is sealed with a resin molding has been developed in an effort to simplify the construction and improve productivity.
For instance, as shown in FIG. 15, the resin molding type of semiconductor laser device 11 disclosed in Japanese Laid-Open Patent Application No. Hei7-170019 has the laser chip 2 mounted to a lead frame 13 via a sub-mount layer 12, and the laser chip 2 is sealed along with the upper portion of this lead frame 13 by a transparent resin molding 14. Furthermore, this resin molding 14 is formed in the same shape as in the above-mentioned can type, so interchangeability is ensured so that mounting to the device housing 8 can be performed just as with a can type.
As shown in FIG. 16, the resin molding type of semiconductor laser device 21 disclosed in Japanese Laid-Open Utility Model Application No. Hei2-54263 has a convex component 23 that serves as a heat-radiating fin formed on both sides of a lead frame 22, and these convex components 23 protrude to the outside of a resin molding 24, which enhances the heat radiation of the laser chip 2 sealed by the resin. The resin molding type of semiconductor laser devices 11 and 21 discussed above offer a simple construction and good productivity.
However, although interchangeability is good with the semiconductor laser device 11 in Japanese Laid-Open Patent Application No. Hei7-170019 because the resin molding 14 is formed in the same shape as that of a can type, the thermal radiation of the laser chip 2 sealed by this resin molding 14 is difficult. Furthermore, with the semiconductor laser device 11, the lead frame 13 to which the laser chip 2 is fixed is inserted into the resin molding 14, but it is difficult to position the lead frame 13 accurately with respect to this resin molding 14. Accordingly, the positioning precision of the laser chip 2 with respect to the resin molding 14 is low, and it is difficult to direct the laser light at the proper location when the semiconductor laser device is mounted in the device housing 8 at the resin molding 14 portion.
In contrast, since convex components 23 that serve as heat-radiating fins are formed on the lead frame 22 with the semiconductor laser device 21 discussed in Japanese Laid-Open Utility Model Application No. Hei2-54363, the heat generated by the laser chip 2 can be eliminated very well, and the lead frame 22 can be inserted at the proper location with respect to the resin molding 24 by means of these convex components 23. However, since the convex components 23 of the lead frame 22 stick out on both sides of the resin molding 24, it is difficult for the shape thereof to be formed the same as that of a can type and thereby ensure interchangeability.
Also, with the resin molding type of semiconductor laser devices 11 and 21 discussed above, the laser chip 2 is also sealed with the resin moldings 14 and 24 along with the lead frames 13 and 22, but this is undesirable since the laser chip 2 is subjected to high temperature and pressure during the molding of the resin moldings 14 and 24 with this configuration, and there is the possibility of breakage.